Particle Image Velocimetry Investigation of Turbulent Boundary Layer Manipulated by Spanwise Wall Oscillations

Particle image velocimetry has been applied to the study of a canonical
turbulent boundary layer and to a turbulent boundary layer forced by
transversal wall oscillations.~This work is within the research framework
going on at the Politecnico di Torino aerodynamic laboratory with the
objective of investigating the response of near wall turbulence to
external perturbations. Results are presented for the optimum oscillation
period of 100 viscous time units and for an oscillation amplitude of 320
viscous units. As expected, turbulent velocity fluctuations are
considerably reduced by the wall oscillations. Particle image velocimetry
has permitted comparisons between the canonical and forced flows with an
attempt to observe the physical mechanisms by which the wall oscillation
influences the near wall organized motions.